Expansion to the shooter S.T.A.L.K.E.R. Shadows of Chernobyl, Clear Sky gameplay perpetuates the need and the atmosphere surrounding the original title by adding a system of varied objectives, where you choose one of several factions to ally themselves and survive in a hostile setting, with enemies with enhanced AI and scenarios remade .

For those who do not have the original version, good news: Clear Sky does not require the original version to be played, making it a standalone game and an expansion at the same time, as have many sites already known to the veterans, serving more as a complement to the original story, and a new experience for the beginners of the series.

The story takes place one year before the events of Shadows of Chernobyl and traces the events of a war of factions, all ambitious for the hegemony of power and wealth in a historic moment of chaos and despair. In this environment, the player chooses one of eight groups in the role of a mercenary and complete missions on a non-linear, with enemies that control territory in the order you prefer.

The game contains about half of levels and new sites to be explored, as well as textures and renewed an engine adapted to support DirectX 10. To complete, as there is new features: rapid travel between the territories, enemies can throw grenades and weapons and armor to repair and open to upgrades (updates).